A holding pattern is traditionally a racetrack-shaped pattern that is flown by an aircraft at a designated location and according to very precise timing while awaiting landing authorization at an airport. Air traffic controllers often utilize holding patterns to properly space and queue aircraft. As part of the Airman Certification Standards (ACS) requirements for an instrument rating, pilots must demonstrate an understanding and the required proficiency to fly a holding pattern.
There are many training methods to provide a pilot with the knowledge of how to visualize the holding pattern and enter the holding pattern. The required skills are provided by the Federal Aviation Administration (FAA). The FAA publishes an Aeronautical Information Manual (AIM), which provides the fundamental flight information and air traffic control procedures required for every pilot to be able to fly in airspace system of the United States. Similarly, the FAA publishes the Instrument Rating Airman Certification Standards to provide the standards for the instrument rating in the airplane category.
To be proficient in the instrument rating, one of the required skills is defined in IR.III.B.S5, which states, “Uses proper wind correction procedures to maintain the desired holding pattern, and to arrive at the holding fix as close as possible to a specified time.” The AIM provides some guidelines for estimating the outbound wind correction angle (OWCA), but there are no guidelines as under what conditions this rule-of-thumb should apply. In addition, there are no guidelines in the AIM for estimating the outbound time other than to fly a one-minute or one-minute and 30 second outbound leg for the initial circuit. The technique utilized to converge to the holding pattern solution is based on a bracketing technique, or “Bracketing Method,” which in reality is a trial and error method. Using the technique, the pilot flies a specified outbound OWCA and outbound time and based on the inbound time and whether the aircraft has undershot/overshot the centerline of the inbound course, the pilot will fly the next circuit with an updated outbound time and OWCA. The process continues until the pilot converges to the correct holding pattern solution. Depending on the initial guess for the outbound time and OWCA, the pilot may require a significant number of circuits before converging to the correct holding pattern. This process of converging to the proper holding pattern can impose a considerable load on the pilot, especially when attempting to troubleshoot a problem, or while reviewing the approach plate prior to executing the approach.